A multi-gear reversing gear system that can be shifted under load is known from DE 44 44 843 A1. To produce a short structure in the axial direction a single shifting clutch, a loose wheel and up to two fixed wheels are arranged on each countershaft. Gearwheels of the reversing gear system form a drive input gearset, a distribution gearset and a drive input gear chain. Besides the transmission ratio of the input gearset, to obtain a different transmission ratio related to another shifting clutch, besides the drive input gearset an independent drive chain consisting of a fixed wheel and a loose wheel with a shifting clutch is provided. With the same structure in principle, different transmission variants with different numbers of gears and different axle spacings can be made. The reversing gear system is particularly suitable for use in construction machines.
A motor drives an input shaft of the reversing gear system, this input shaft being connected in a rotationally fixed manner to a pump wheel of a hydrodynamic torque converter. A turbine wheel of the hydrodynamic torque converter transmits the drive power to a hollow shaft positioned concentrically with the input shaft.
Unfortunately, during braking operation of a vehicle made with the reversing gear system or during the operation of its brakes, there is no recuperation function for the recovery of energy.
A hydrostatic drive with recovery of braking energy is described in DE 10 2005 060 992 A1. The hydrostatic drive comprises a hydro-pump and a hydro-motor connected with one another by a first working line and a second working line. In addition, the hydrostatic drive comprises a storage element for the storage of pressure energy, which is connected to an inlet-side connection of the hydro-pump for the recovery of the stored energy.
By means of the hydrostatic drive a vehicle can be driven in both the forward and the reverse directions, and this forward and reverse driving of the vehicle can be carried out with or without the involvement of the storage element. This means that by the hydrostatic drive, starting from the hydro-pump, a torque of the working machine actively connected with the hydro-pump can be transmitted to the hydro-motor and from there, during traction operation, to the drive input of the vehicle. In contrast, starting from the drive input of the vehicle, a drive output torque can be transmitted by the hydro-motor and supported in the area of the working machine.
During both traction and thrust operation of the vehicle drivetrain made with the hydrostatic drive, energy in the form of hydraulic pressure can be stored in the area of the storage element, or the closed hydraulic circuit that connects the hydro-pump and the hydro-motor to one another can be pressurized and this pressure converted into torque in the area of the hydro-pump and the hydro-motor.
When the hydrostatic drive relates to a vehicle drive, the adjustable hydro-motor is connected via a drive output shaft to a vehicle drive, which can be a wheel drive, a differential transmission or a downstream power shift transmission or manual transmission.
The hydrostatic drive is of complex design and structure, and in addition can only be operated by virtue of elaborate control and regulation means, which however, is undesirable.
Furthermore, a drive torque of the working machine always has to be passed by the hydrostatic drive in the direction of the vehicle drive, whereby the efficiency of a vehicle drivetrain made with the hydrostatic drive is reduced by comparison with the reversing gear system designed in accordance with DE 44 44 843 A1.